Synthetic Antenna Functioning As Light Harvester in the Whole Visible Region for Enhanced Hybrid Photosynthetic Reaction Centers

Omar, Omar Hassan; Gatta, Simona la; Tangorra, Rocco Roberto; Milano, Francesco; Ragni, Roberta; Operamolla, Alessandra; Argazzi, Roberto; Chiorboli, Claudio; Agostiano, Angela; Trotta, Massimo; Farinola, Gianluca M.

doi:10.1021/acs.bioconjchem.6b00175

Cited by 38 publications

(21 citation statements)

References 64 publications

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“…sphaeroides RC . Published approaches include the direct attachment of blue‐absorbing or green/red‐absorbing synthetic dyes to lysine residues on a carotenoid‐less RC, the direct attachment of green/red or red/near‐IR‐absorbing dyes to cysteine residues engineered on native RCs and the attachment of pairs of dyes carried on a DNA nanoscaffold . These provide a means of adding multiple chromophores to an RC, although it is difficult to control their spatial arrangement when multiple attachment sites are present.…”

Section: Discussionmentioning

confidence: 99%

Mechanisms of Self‐Assembly and Energy Harvesting in Tuneable Conjugates of Quantum Dots and Engineered Photovoltaic Proteins

Liu

Mantell

Bartolo

et al. 2018

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pigments is of interest to diverse alternative solar energy technologies including photoelectrochemical cells, [4][5][6][7][8][9][10][11][12][13] biosensing, [14,15] photosensing, [16] molecular electronics, [7] and solar fuel synthesis. [17][18][19] Studies have focused in the main on Photosystem I from cyanobacteria [20][21][22] and the RC and RC-LH1 complexes from purple photosynthetic bacteria such as Rhodobacter (Rba.) sphaeroides [23][24][25][26] (Figure 1a,b). This latter organism is a popular source of photoproteins because it is possible to apply extensive protein engineering to its well-characterized RC, enabling high-yield expression and purification of proteins with specifically tailored properties or substantial modifications.A feature of natural photosystems is selective harvesting of certain regions of the solar spectrum, the most obvious illustration being the predominant green color of plant photosynthetic tissues that arises from relatively strong absorbance of red and blue light by chlorophyll and carotenoid pigments. As Rba. sphaeroides synthesizes bacteriochlorophyll (BChl) as its primary photosynthetic pigment its RC exhibits strong absorbance in the near-infrared between 700 and 950 nm, and in the near-UV below 420 nm, but its absorbance across the visible region is relatively weak (Figure 1c). A limitation in the use of this protein in device technologies is therefore suboptimal harvesting of light energy across much of the region where the solar radiation at the earth's surface is maximal, [27] and this limitation is manifest in action spectra of photocurrent density in photoelectrochemical cells based on Rba. sphaeroides pigment-proteins. [28][29][30][31][32][33] In this study we investigated directed self-assembly of conjugates between genetically engineered Rba. sphaeroides RCs and water-soluble cadmium telluride (CdTe) quantum dots (QDs). The tuneable optical properties of these semiconductor nanocrystals have been exploited in a variety of technologies including solar cells and diverse biological applications. [34][35][36] The particular QDs employed in the present work have broad absorbance across the visible spectrum and an emission band centered at 750 nm that overlaps with RC absorbance bands centered at 760 and 800 nm (Figure 1c). These QDs therefore were capable of acting as a synthetic light harvesting system for energy transfer [37,38] and charge separation [23][24][25][26] in the Rba. sphaeroides RC (Figure 1b).Photoreaction centers facilitate the solar energy transduction at the heart of photosynthesis and there is increasing interest in their incorporation into biohybrid devices for solar energy conversion, sensing, and other applications. In this work, the self-assembly of conjugates between engineered bacterial reaction centers (RCs) and quantum dots (QDs) that act as a synthetic light harvesting system is described. The interface between protein and QD is provided by a polyhistidine tag that confers a tight and specific binding and defines the geometry of the interactio...

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Section: Discussionmentioning

confidence: 99%

Mechanisms of Self‐Assembly and Energy Harvesting in Tuneable Conjugates of Quantum Dots and Engineered Photovoltaic Proteins

Liu

Mantell

Bartolo

et al. 2018

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“…Artificial proteins have been designed with a variety of cofactors participating in specific, self-contained functional features [3,15,16]. Similarly, artificially expanding the reaction center template has been accomplished by the attachment of molecules to the surface to enhance light capture and energy transfer [50][51][52][53][54]. Energy transfer has also been demonstrated for the fusion of a fluorescent yellow protein and a light-harvesting protein with the reaction center [55,56], as well as a four-helix bundle with a bound fluorescent cofactor fused to a light-harvesting protein [57].…”

Section: Discussionmentioning

confidence: 99%

A bound iron porphyrin is redox active in hybrid bacterial reaction centers modified to possess a four-helix bundle domain

Allen

Chamberlain

Olson

et al. 2021

Photochem Photobiol Sci

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In this paper we report the design of hybrid reaction centers with a novel redox-active cofactor. Reaction centers perform the primary photochemistry of photosynthesis, namely the light-induced transfer of an electron from the bacteriochlorophyll dimer to a series of electron acceptors. Hybrid complexes were created by the fusion of an artificial four-helix bundle to the M-subunit of the reaction center. Despite the large modification, optical spectra show that the purified hybrid reaction centers assemble as active complexes that retain the characteristic cofactor absorption peaks and are capable of light-induced charge separation. The four-helix bundle could bind iron-protoporphyrin in either a reduced and oxidized state. After binding iron-protoporphyrin to the hybrid reaction centers, light excitation results in a new derivative signal with a maximum at 402 nm and minimum at 429 nm. This signal increases in amplitude with longer light durations and persists in the dark. No signal is observed when iron-protoporphyrin is added to reaction centers without the four-helix bundle domain or when a redox-inactive zinc-protoporphyrin is bound. The results are consistent with the signal arising from a new redox reaction, electron transfer from the iron-protoporphyrin to the oxidized bacteriochlorophyll dimer. These outcomes demonstrate the feasibility of binding porphyrins to the hybrid reaction centers to gain new light-driven functions.

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“…39 A possible way to enhance the spectral response of the protein in a BPEC is to physically attach dyes sufficiently close to the protein surface to enable energy transfer through mechanisms such as FRET. Such modified RCs have been engineered and shown to engage in enhanced energy capture [45][46][47][48][49][50] but have not been tested in a BPEC. In the present work, we have established the feasibility of an alternative approach in which the small molecule electrolyte fulfills a dual function as a redox mediator and an energy harvester.…”

Section: Discussionmentioning

confidence: 99%

High-Performance UV Enhancer Molecules Coupled with Photosynthetic Proteins for Ultra-Low-Intensity UV Detection

Suresh

Vaghasiya

Nandakumar

et al. 2019

Chem

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Dual attributes of UV-photo-responsive organic-ionic conductors are exploited in bio-photoelectrochemical cells based on photosynthetic RC-LH1 proteins from Rhodobacter sphaeroides. These UV enhancer molecules (UVEM) can generate small photocurrents in the absence of protein and are also effective electrolytes for photocurrent generation by RC-LH1 complexes in response to near-infrared excitation. Mixing RC-LH1 and UVEM components strongly enhanced UV photocurrents relative to those obtained with protein or UVEM alone, an effect that is attributed to energy transfer from the hetero-anthracene chromophore of the UVEM to the carotenoids of the RC-LH1 complex. RC-LH1/ UVEM bio-photoelectrochemical cells were superior to conventional RC-LH1 cells in terms of UV external quantum efficiency, photo-response sensitivity, and photocurrent rise-decay times. These bio-photodetectors could detect weak UV radiation with intensities as low as 2 mW/cm 2 . This combination of photosynthetic proteins with dual-function electrolytes is the first attempt to construct fully functional bio-photoelectrochemical UV photodetector based on natural components.

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Synthetic Antenna Functioning As Light Harvester in the Whole Visible Region for Enhanced Hybrid Photosynthetic Reaction Centers

Cited by 38 publications

References 64 publications

Mechanisms of Self‐Assembly and Energy Harvesting in Tuneable Conjugates of Quantum Dots and Engineered Photovoltaic Proteins

Mechanisms of Self‐Assembly and Energy Harvesting in Tuneable Conjugates of Quantum Dots and Engineered Photovoltaic Proteins

A bound iron porphyrin is redox active in hybrid bacterial reaction centers modified to possess a four-helix bundle domain

High-Performance UV Enhancer Molecules Coupled with Photosynthetic Proteins for Ultra-Low-Intensity UV Detection

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